Subject: sched: make cpu_clock() not use the rq clock
From: Ingo Molnar <[email protected]>
it is enough to disable interrupts to get the precise rq-clock
of the local CPU.
this also solves an NMI watchdog regression: the NMI watchdog
calls touch_softlockup_watchdog(), which might deadlock on
rq->lock if the NMI hits an rq-locked critical section.
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
Index: linux-rt-rebase.q/kernel/sched.c
===================================================================
--- linux-rt-rebase.q.orig/kernel/sched.c
+++ linux-rt-rebase.q/kernel/sched.c
@@ -446,13 +446,12 @@ static inline unsigned long long rq_cloc
*/
unsigned long long cpu_clock(int cpu)
{
- struct rq *rq = cpu_rq(cpu);
unsigned long long now;
unsigned long flags;
- spin_lock_irqsave(&rq->lock, flags);
- now = rq_clock(rq);
- spin_unlock_irqrestore(&rq->lock, flags);
+ local_irq_save(flags);
+ now = rq_clock(cpu_rq(cpu));
+ local_irq_restore(flags);
return now;
}
-
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